<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        a:link {
            color: black;
            text-decoration: none;
        }
        a:visited {
            color: green;
            text-decoration: none;
        }
        a:hover {
            color: yellow;
            text-decoration: overline;
        }
        a:active {
            color: red;
            text-decoration: line-through;
        }
    </style>
</head>
<body>
    <p><a href="https://gitee.com">这是一个链接</a></p>
    <p><b>注意：</b> a:hover 必须在 a:link 和 a:visited 之后，需要严格按顺序才能看到效果。</p>
    <p><b>注意：</b> a:active 必须在 a:hover 之后。</p>
</body>
</html>